This study will analyze the monoclonal immunoglobulins in the serum of patients who have biclonal or triclonal gammopathy. We will ultimately determine if biclonal or triclonal immunoglobulins from the same patient share identical idiotypic determinants and whether the light or heavy chains of these proteins share identical VL or VH regions. The combinations of immunoglobulins studied to date include IgA(kappa) plus IgG(kappa); IgM(kappa) plus IgA(kappa) plus IgG(kappa); IgG1(kappa) plus IgG2(kappa) plus IgG2(kappa). The N-terminal amino acid sequences up to residue No. 45 of the GR alpha- and gamma-chains are known. We will determine the remainder of the amino acid sequence of the VH regions by sequencing cyanogen bromide fragments of the two chains or tryptic peptides of cyanogen bromide fragments. The N-terminal amino acid sequence up to residue No. 40 of the two GR kappa-chains is known. We intend to determine the sequence of the remaining amino acids in the VL region of these two chains by sequencing peptides generated by digestion with trypsin. With the triclonal proteins, we will determine if the three kappa-chains are identical by isoelectric focusing, mapping of iodinated tryptic and chymotryptic peptides and N-terminal amino acid sequence. We will determine the N-terminal amino acid sequence of the mu-, alpha-, and gamma-chains. If the sequences are identical, we will determine the sequence of the remaining amino acids in the VH regions of these chains from peptides produced by cyanogen bromide cleavage. We have shown that the two IgG2 molecules in patient GT's serum possess identical idiotype determinants and that the IgG1 molecule possesses a related idiotypic determinant. We will analyze the heavy and light chains of these three molecules to determine if they have identical N-terminal amino acid sequences and ultimately, identical variable regions.